Anti-vapor-lock fuel filter



Aug. 22, 1961 O. D. LOVEDAY ANTI-VAPOR-LOCK FUEL FILTER Filed June 5, 1957 MMA um Patented Aug. 22, 1961 hcc 2,997,180 ANTI-VAIR-LOCK FUEL FILTER Qliver D. Loveday, Detroit, Mich., assigner to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Filed June 3, 1957, Ser. No. 663,076 ZICIaims. (Cl. 21d-436) This invention relates to fuel supply systems and particularly to a filter element to be incorporated in a fuel system that will prevent the development of that objectionable condition in a fuel system that is known as vapor-lock.

It is a primary object of this invention to provide a filter element for the fuel supp-ly system :of a motor vehicle, or the like, that will prevent the development of a vapor-lock condition in the fuel system.

It is still another object of this invention to provide a filter element of substantially conventional design having a vent associated therewith that will prevent the development of a vapor-lock condition in the fuel supply system without altering the normal operation o`f the fuel supply system.

It is still another object o-f this invention to provide the housing of a substantially conventional fuel filter element with a restricted bleed vent and a discharge conduit such that any 'vapor that develops in the fuel supply system may be bled out of the supply system before it can block flow therethrough, the bleed-off being discharged to the fuel supply reservoir.

It is another object of this invention to provide an antivapor-lock fuel filter that is simple in design, economical to manufacture and install, adaptable to any conventional fuel supply system, reliablein operation and free of any fire hazards.

It is still another object of this invention to provide an anti-vaporlock device that has no moving parts and that is readily incorporated in the conventional motor vehicle fuel supply system.

Other `objects and advantages of this invention will becorne readily apparent from a reading of the following description and' a consideration of the related drawings wherein:

FIG. l is a diagrammatic View of a motor vehicle engine fuel supply system embodying this invention; and

FIG. 2 is an enlarged sectional elevational view of the fuel filter element that forms the major part of this invention.

It is well known to most motor vehicle operators that engine operation, under the influence of excessive heat, as for instance when traveling in hot weather, or when pulling eXtra heavy loads, or when climbing steep and long hills, or permitting the vehicle engine to idle for excessive periods, causes the liquid fuel in the engine fuel supply yline to vaporize. This fuel vaporization tends to interfere with the proper feeding and functioning of the engine. This vaporization in the fuel supply line can develop a condition known as vapor-lock which can cause the engine to stall. Furthermore, after such a stall subsequent starting may be prevented until after the vaporized fuel is condensed or bled rofl". This invention relates to a simple means that can be readily adapted to the con- Ventional motor vehicle fuel supply system so that the development of a vapor-lock condition will be prevented.

Vapor can be formed in the fuel in the tank and in the fuel lines from the tank to the engine. The fuel lines, fuel pumps, and fuel filters of the supply system must be capable of handling this vapor and at the same time supplying the carburetor with an adequate quantity of liquid fuel. Vapor handling ability determines the size of the several supply system units. Volumetric eXpansion in passing from the liquid phase to the vapor phase is approximately 200 to 1. With only 10% vaporization the volumetric expansion would still be 20` to l. Assuming a fuel pump is as efficient for use as a vapor pump as it is as a liquid pump, and assuming 100% to be the capacity required to handle liquid only, then to handle liquid with 10% vaporization would require a pump with 20 times the capacity of the pump required to handle liquid fuel. This tremendous increase in required capacity of the system to handle only 10% vaporization makes it apparent that serious consideration should be given to the separation of the liquid and vapor states and to the provision for separate means for handling the different fuel states or phases.

lt is herein proposed to provide a lter with a reservoir having a valve for separation and collection of the vapor phase and means for by-passing the vapor back to the fuel tank or to the air horn of the carburetor or to the atmosphere.

In FIG. l of the drawings, the reference numeral 10 represents a fuel pump that is arranged to be driven by the eccentric cam 11 that is preferably driven by the engine E associated with the disclosed fuel supply system. Fuel pump 10 has its suction side connected to a liquid fuel supply conduit 12 that is connected to the fuel supply storage tanks or reservoir. The particular fuel system shown is a dual tank system that is cornrnon on trucks and tractor-trailer combinations although the invention disclosed is equally applicable to a single tank system such as that used on most passenger cars.

In the fuel system shown in FIG. l the supply conduit 12 is connected to a dual tank fuel supply selector valve 13 which provides for selective connection of the fuel pump 10 to fuel tank A or fuel tank B. Conduit 15 connects selector valve 13 to fuel tank A while conduit 16 connects selector valve 13 to fuel tank B. Fuel tanks A and B each have a ller cap 18.

Liquid fuel supplied to the 4fuel pump 10` by suction or supply conduit 12 is transmitted through conduit 21 to the inlet port 22 (see FIG. 2) in the cover 23 of the fuel filter housing 24. Fuel supplied to filter housing inlet port 22 is deposited in the filter bowl interior area 25. Area 25 can be referred to as the receiving area of the filter. Filter bowl 26 is usually of a transparent material such as glass or a clear plastic material. Bowl 26 is detachably connected to the `cover 23 by the bail 27 and the attached set screw 28. The top edge of the bowl 26 is arranged to sealingly seat on a seat washer 29 received in a recess 30 in the underside of cover 23. Washer 29 may be of a compressible material such as rubber, plastic or cork.

Mounted within the cuplike bowl 26 is a smaller cupshaped filter element 31. Filter element 31 may be of some ceramic material or any other filter material that will separate water, dirt and other foreign material from the liquid fuel supplied to the bowl receiving area 25. Filter 31 is preferably designed so that it will be pcrvious to only pure fuel and impervious to all other matter, liquid or solid. It will be noted that a compression spring 33, `mounted in the closed end of the filter bowl 26, engages a seat 34 formed in the closed end of the filter element 31. Spring 33 urges the upper end edge of the cup-like filter 31 into sealing engagement with the seal 29 in recess '30. It will be noted that the recess 30 in cover 23 of the filter housing 24 is of suitable size to receive the upper end edges off the filter bowl 26 and filter element 31, in spaced relationship. This recess 30 also restricts relative movement of the parts 26 and 31 and keeps these parts located so that liquid fuel from supply port 22 may pass `into the bowl receiving area 25 and then through the filter 31 to the inner filter chamber 38. Liquid fuel passed into the filter chamber 3S can normally pass from this chamber into the discharge con- 3 duit 40 lthat projects into the lower portion of the filter charnber 38.

Filter discharge conduit 40 may be an integral or a separable part of the filter cover 23. Discharge conduit 40 is connected to the supply line conduit 42 which discharges in to the fuel supply portion of the carburetor 45.

Connected to the upper pontion of the filter chamber 38, through the cover 23, is a vapor bleed-off conduit 51. Vapor bleed-off conduit 51 is connected to a selector valve 53 that provides for alternate connection of the vapor bleed conduit 51 to either of the fuel supply tanks A or B. Branch conduit 54 connects selector valve 53 to tank A while branch conduit 55 connects selector valve 53 to tank B. It lwill be noted that the connection of the filter chamber 38 to the bleed conduit 51 is by way of a restriction orifice v57. The restriction orifice 57 slows down the escape of liquid fuel and vapor from the upper portion of the filter chamber 38 so that the capacity of the fuel pump 10 does not have to be materially increased to provide the required carburetor fuel supply when this invention is used. While the restriction 57 slows down bleed-off through conduit 51, still, the bleed-off line 51 will prevent the development of a vapor block in the chamber 38 such that adequate fuel supply is blocked from passage into discharge line 40, 42.

From the foregoing description of FIGS. 1 and 2, it is thought to be obvious that if vapor in the fuel tanks, fuel lines or fuel pump is passed through the fuel supply system to the filter chamber 38, it can escape from the top of the chamber 38, along with some liquid fuel, by way of the restriction orifice 57. This Vapor and some entrained liquid fuel will be discharged by conduit 51 at some point where it will not interfere with the safe, reliable operation of the vehicle. Without a bleed-off port, such as the orifice `'57, the vapors that are passed through the fuel lines to the filter 24 would tend to fill up the filter chamber 38 and prevent the entrance of liquid fuel into the chamber 38 and into the discharge line 40, 42. If chamber 38 becomes full of vapor then sufficient fuel to operate the engine cannot be passed to the carburetor 45 and the engine will stall. Worse yet, until the filter 24 cools so that the fuel vapors condense in the fuel chamber 38 there will be no practical way to start the engine. The invention herein disclosed provides a simple, foolproof way of eliminating vapor-lock by merely adding a restriction orifice and suitable bleed-off return tubing from the filter to the fuel storage tanks. It is thought to be obvious that the bleed-off line 51 should be connected back to the fuel tanks A and B so that there will notbe a waste of the fuel that is bled off through the filter `orifice 57. It is clear 4that it would be quite dangerous, as well as ineicient, to discharge the bled-cff fuel to the atmosphere in the vicinity of the filter because of the adjacent location of the hot engine. Also, such a practice would discharge kfuel fumes adjacent the drivers compartment where they would drift or be blown or sucked into the drivers compartment through various air conduits that are usually communicatively connected between the engine compartment and the dn'vers compartment.

From FIG. l it will be noted that the system shown is for a dual tank system wherein either tank A or tank B can be selectively connected to the fuel supply line 12 by the selector valve 13. Likewise, the selector valve 53 permits discharge of the filter bleed-off into either one of Cil the tanks A or B by way of conduits 54 or 55. Normally the bleed-off would be returned to the fuel tank from which the fuel supply is then being pumped. However, it is possible that the fuel could be pumped from one tank and the bleed-off returned to the other tank so that the vapors bled off would be deposited in a tank not then in use. This would give a longer time for condensation of the bled-off fuel before it is returned to the fuel supply system.

I claim:

1. A vapor separating lter unit adapted to be placed in a liquid fuel supply line between the fuel pump and the fuel vaporizing unit comprising a cup-shaped bowl having a detachable cover sealingly connected thereto, a

;- cup-shaped filter element arranged concentrically within and spaced from said bowl and `sealingly engaged with said bowl cover so as to provide an inner filter chamber and an outer receiving chamber, a fuel inlet port in said cover connected to said outer receiving chamber, a fuel outlet port connected through said cover to the lower portion of the inner filter chamber, and an open vapor bleed port through the portion of the cover overlying the inner filter chamber separate from the full outlet port, said bleed port providing a restricted vapor bleed orifice in the upper portion of said inner filter chamber to restrict the passage of liquid fuel therethrough while permitting the passage of fuel vapor from the inner filter chamber and conduit means connecting said bleed port to a closed container.

2. A vapor separating filter unit adapted to be placed in a liquid fuel supply line between the fuel pump and the fuel vaporizing unit comprising a cup-shaped bowl having a `detachable cover sealingly connected thereto, a cup-shaped filter element arranged concentrically within and spaced from said bowl and resilient means in said bowl acting on said filter to cause it to be sealingly engaged with said bowl cover soas to provide an inner filter chamber and an outer receiving chamber, a fuel inlet port in said cover connected to said outer receiving chamber, a fuel outlet port connected through said cover to the lower portion of the inner filter chamber, and an open vapor bleed port through the portion of the cover overlying the inner filter chamber separate from the fuel outlet port, said bleed port providing a restricted vapor bleed orifice to restrict the passage of liquid fuel therethrough whilepermitting the passage of fuel vapor from the inner filter chamber and conduit means connecting said bleed port to a plurality of closed containers with valve means in said conduit means to provide for selective discharge into said containers.

References Cited in the file of this patent UNITED STATES PATENTS 1,623,074 Tartrais Apr. 5, 1927 1,849,590 Phillips Mar. 15, 1932 1,910,553 Lentz May 23, 1933 2,323,525l Ebel et al. July 6, 1943 2,647,566 Haynie Aug. 4, 1953 2,707,050 Mailhot et al. Apr. 26, 1955 FOREIGN PATENTS 127,137 Australia Apr. 8, 1948 711,131 Great Britain June 23, 1954 ERNEST W. SWIDER Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No. 2,997,180 August 22, 19W

Oliver D. Loveday It is hereby certified that error appears n the above numbered patent requiring correction and that the said Letters- Patent Should read as 'corrected below.

Column 4, line 23, for "full" read fuel line 37, for "seas" read so as Signed and sealed ILhis 23rd day of January 1962.

C SEAL) Attest:

DAVID L. LADD Commissioner of Patents 

